Bosch Sanding Belts are butt-spliced for bi-directional sanding. That means that the belt is joined using a diagonal seam which is much stronger and results in smoother running both forward/backward and side-to-side. In other words, they last longer and it’s less likely that the belt will come apart at the seams. The aluminum oxide open coat grit resists loading up with sawdust and removed materials. The double resin bonding and X-weight cloth backing mean long life and less belt changes. Works great on wood, metal, plastic, fiberglass, whatever you have to sand. Sold in packs of 3. Made in Italy.